The present invention relates to a high moisture transmission laminate film having utility in medical applications, in particular as part of a laminate construction from which surgical and other protective garments can be manufactured.
In the medical field, there is great concern about the transmission of infectious agents and the need for protecting doctors and surgeons from these infectious agents during the treatment and examination of patients. Efforts have been made to develop surgical gowns and drapes which contain barriers against the transmission of infectious agents. One such effort is exemplified in published European Patent Application 0 398 611 to Woodcock. The invention described therein relates to a surgical or hygienic barrier artefact comprising a fabric operative to prevent the passage of infectious agents through it from one side of the fabric to the other. The artefact is made from a substrate and a non-porous coating of the type which transports water only in the vapor phase. The Woodcock invention is based upon the discovery that certain materials, which have the capacity to transmit water in the vapor phase as well as gases soluble therein, operate as effective barriers to viral agents. In the Woodcock invention, the coating may be a hydrophilic polyurethane, while the substrate may comprise a closely woven nylon, polyester, or other synthetic or natural fiber.
Similar concerns have given rise to the development of improved wound dressings. One such dressing is illustrated in U.S. Pat. No. 4,867,150 to Gilbert. The Gilbert wound dressing comprises a pad of absorbent gas-permeable fabric formed from fibers held in place by interlocking and frictional engagement with each other and an elastomeric, soft, substantially non-absorbent, foraminous thin polyurethane film attached thereto. In one embodiment of the Gilbert dressing, a combination of polyesters, nylon or rayon are thermally bonded to a Hytrel brand copolyester.
Other types of composite film material which have been suggested for use as a construction fabric for medical apparel or for other articles of clothing are set out in U.S. Pat. Nos. 4,925,732 to Driskill et al. and 5,169,712 to Tapp. The Driskill patent relates to a laminate that has particular utility in shoes. The laminate comprises flexible moisture permeable adherent layers bonded together by a moisture permeable or breathable adhesive. The Tapp patent describes a porous film composite comprising at least one layer of an oriented microporous film having microvoid cells and interconnecting pores between the cells.
There still remains a need for improved laminate materials that may be used for viral barrier surgical garments.